Obesity levels are estimated to have tripled since 1975 and that in 2016 13% of the world's population was considered obese. We eat too much and badly, foods rich in fats, sugars and refined flours, and we do little physical activity. The problem with obesity is that it is linked to a low but constant level of inflammation, which does not immediately give symptoms but acts silently and in the long run can cause type 2 diabetes, cardiovascular disease and cancer. In addition to practicing moderate physical activity and following a varied and healthy diet, at our disposal we have very powerful tools offered by nature, such as olive leaves. In fact, olive leaves counteract the inflammation caused by overweight, as evidenced by a very recent research published in the journal Nutrients by a team from the University of Naples Federico II (De Cicco et al, Nutrients, Nov 2020).
There are particular cells of the immune system, called macrophages, which divide into M1 macrophages, or mediators of inflammation, and M2 macrophages, with anti-inflammatory action. Normally, in the absence of obesity, M2 macrophages prevail in the adipose tissues, guaranteeing the maintenance of physiological conditions and a proper sensitivity to insulin. However, in case of obesity, M1 macrophages prevail in adipose tissues, which release pro-inflammatory substances such as free radicals, TNF alpha and interleukins, thus creating a persistent inflammatory state that, as we know from previous studies, can weaken the immune system. In addition, the greater the ratio between M1 macrophages and M2 macrophages, the stronger the body's resistance to insulin. Therefore, being able to reduce inflammation and acting on the ratio between M1 and M2 macrophages, in favor of the latter, is a strategy to control inflammation and related effects. In nature there are several substances with anti-inflammatory action, such as omega 3 fatty acids, flavonoids, prebiotics and probiotics but also, as stated in today's article, olive leaves. In fact, the olive leaves contain phenolic compounds, with an antioxidant and anti-inflammatory action, in higher quantities than another olive product, the famous extra virgin olive oil. To give an example, oleuropein, which is the most abundant phenolic compound in the olive tree, is detectable in the extra virgin olive oil in a percentage between 0.005% and 0.12% while in the olive leaves between 1% and 14%. Well, what the researchers observed is that the intake of olive leaf extracts in case of obesity suppressed the release of inflammatory mediators, TNF alpha, interleukins and free radicals. Not only that, olive leaves counteract oxidative stress and, above all, promote the conversion of macrophages from M1, the pro-inflammatory type, into M2, the anti-inflammatory macrophages.
Therefore, olive leaves are considered a promising remedy in case of obesity to reduce the ratio of M1 and M2 macrophages, counteract chronic inflammation and related diseases such as diabetes, tumors and cardiovascular diseases.